Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes.One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the...Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes.One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel system.In this study,shaking table tests were designed and performed based on a tunnel under construction in Dalian,China.Numerical models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting system.The results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude increased.In addition,the existing tunnel acceleration,earth pressure,and internal force were hardly affected by the change in the burial depth;for the new tunnel,the acceleration and internal force decreased as the burial depth increased,while the earth pressure increased.This shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative area.Overall,when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels,the change in the burial depth of the new tunnel had little effect on the existing one,and the tunnel structure was deemed safe.These results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.展开更多
Since the development of the new Austrian tunnelling method(NATM)in the 1960s,this technique has been applied successfully in many tunnels.However,opinions of NATM principles emerged till 2000,i.e.NATM is not a tunnel...Since the development of the new Austrian tunnelling method(NATM)in the 1960s,this technique has been applied successfully in many tunnels.However,opinions of NATM principles emerged till 2000,i.e.NATM is not a tunnelling method,but an approach covering all general principles of tunnelling.To investigate the general principles of the NATM,this study focused on tunnelling practises in the Bolu tunnel,and evaluated the conditions under which the NATM practises could be effective.The Bolu tunnel project was designed following the NATM principles.It is evident that practises adopted in this tunnel are important with respect to the NATM.In addition,it shows that the solutions to the problems encountered in this tunnel are consistent with the NATM principles.Finally,the study determines the ground types of the NATM principles and proposes associated updates.展开更多
Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- ti...Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- tion was developed for tunneling in karst area. Then, a new system of ventilation by involving the dedusting technol- ogy was proposed and used in the field, which received a good air quality. Finally, a method to minimize the dis- tance between the working face and the invert installation was proposed by optimizing the invert installation and adopting the micro bench method. Applying the method to the project obtained an excellent result. The achievement obtained for this study would be able to provide a valuable reference to similar projects in the future.展开更多
Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and ant...Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and anthropogenic impacts are generally reported as the most important triggering factors in the region. Following the portal slope excavations in the entrance section of Cankurtaran tunnel, located in the region, where the highly weathered andesitic tuff crops out, a circular toe failure occurred. The main target of the present study is to investigate the causes and occurrence mechanism of this failure and to determine the feasible remedial measures against it using finite element method(FEM) in four stages. These stages are slope stability analyses for pre-and postexcavation cases, and remediation design assessments for slope and tunnel. The results of the FEM-SSR analyses indicated that the insufficient initial support design and weathering of the andesitic tuffs are the main factors that caused the portal failure. After installing a rock retaining wall with jet grout columns and reinforced slope benching applications, the factor of safety increased from 0.83 to 2.80. In addition toslope stability evaluation, the Rock Mass Rating(RMR), Rock Mass Quality(Q) and New Austrian Tunneling Method(NATM) systems were also utilized as empirical methods to characterize the tunnel ground and to determine the tunnel support design. The performance of the suggested empirical support design, induced stress distributions and deformations were analyzed by means of numerical modelling. Finally, it was concluded that the recommended stabilization technique was essential for the dynamic long-term stability and prevents the effects of failure. Additionally, the FEM method gives useful and reasonably reliable results in evaluating the stability of cut slopes and tunnels excavated both in continuous and discontinuous rock masses.展开更多
Estimation of tunnel diameter convergence is a very important issue for tunneling construction,especially when the new Austrian tunneling method（NATM） is adopted.For this purpose,a systematic convergence measurement...Estimation of tunnel diameter convergence is a very important issue for tunneling construction,especially when the new Austrian tunneling method（NATM） is adopted.For this purpose,a systematic convergence measurement is usually implemented to adjust the design during the whole construction,and consequently deadly hazards can be prevented.In this study,a new fuzzy model capable of predicting the diameter convergences of a high-speed railway tunnel was developed on the basis of adaptive neuro-fuzzy inference system（ANFIS） approach.The proposed model used more than 1 000 datasets collected from two different tunnels,i.e.Daguan tunnel No.2 and Yaojia tunnel No.1,which are part of a tunnel located in Hunan Province,China.Six Takagi-Sugeno fuzzy inference systems were constructed by using subtractive clustering method.The data obtained from Daguan tunnel No.2 were used for model training,while the data from Yaojia tunnel No.1 were employed to evaluate the performance of the model.The input parameters include surrounding rock masses（SRM） rating index,ground engineering conditions（GEC） rating index,tunnel overburden（H）,rock density（？）,distance between monitoring station and working face（D）,and elapsed time（T）.The model’s performance was assessed by the variance account for（VAF）,root mean square error（RMSE）,mean absolute percentage error（MAPE） as well as the coefficient of determination（R2） between measured and predicted data as recommended by many researchers.The results showed excellent prediction accuracy and it was suggested that the proposed model can be used to estimate the tunnel convergence and convergence velocity.展开更多
The New Austrian Tunneling Method （NATM） has been widely used in the construction of mountain tun- nels, urban metro lines, underground storage tanks, underground power houses, mining roadways, and so on, The variat...The New Austrian Tunneling Method （NATM） has been widely used in the construction of mountain tun- nels, urban metro lines, underground storage tanks, underground power houses, mining roadways, and so on, The variation patterns of advance geological prediction data, stress-strain data of supporting struc- tures, and deformation data of the surrounding rock are vitally important in assessing the rationality and reliability of construction schemes, and provide essential information to ensure the safety and scheduling of tunnel construction, However, as the quantity of these data increases significantly, the uncertainty and discreteness of the mass data make it extremely difficult to produce a reasonable con- struction scheme; they also reduce the forecast accuracy of accidents and dangerous situations, creating huge challenges in tunnel construction safety, In order to solve this problem, a novel data service system is proposed that uses data-association technology and the NATM, with the support of a big data environ- ment, This system can integrate data resources from distributed monitoring sensors during the construc- tion process, and then identify associations and build relations among data resources under the same construction conditions, These data associations and relations are then stored in a data pool, With the development and supplementation of the data pool, similar relations can then he used under similar con- ditions, in order to provide data references for construction schematic designs and resource allocation, The proposed data service system also provides valuable guidance for the construction of similar projects.展开更多
The Geheyan Power Station on the Qingjiang river has four inlet tunnels, on the right bank, with its excavation diameter of 11.3 m to 12.5 m, after lining diameter of 9.5 m, axis to axis spacing of 24 m. The thickness...The Geheyan Power Station on the Qingjiang river has four inlet tunnels, on the right bank, with its excavation diameter of 11.3 m to 12.5 m, after lining diameter of 9.5 m, axis to axis spacing of 24 m. The thickness of the pillar between tunnels should usually be more than two times of tunnel diameter to ensure the stability of surrounding rock during excavation. In this paper, the excavation methods of tunnels with the pillar thickness as small as the tunnel diameter, such as smooth surface blasting, shotcrete support protection, are emphatically discussed.展开更多
基金Scientific Research Fund of Liaoning Provincial Education Department under Grant No.LJKZ0336。
文摘Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes.One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel system.In this study,shaking table tests were designed and performed based on a tunnel under construction in Dalian,China.Numerical models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting system.The results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude increased.In addition,the existing tunnel acceleration,earth pressure,and internal force were hardly affected by the change in the burial depth;for the new tunnel,the acceleration and internal force decreased as the burial depth increased,while the earth pressure increased.This shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative area.Overall,when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels,the change in the burial depth of the new tunnel had little effect on the existing one,and the tunnel structure was deemed safe.These results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.
基金General Directorate of Highways(KGM)for their supports。
文摘Since the development of the new Austrian tunnelling method(NATM)in the 1960s,this technique has been applied successfully in many tunnels.However,opinions of NATM principles emerged till 2000,i.e.NATM is not a tunnelling method,but an approach covering all general principles of tunnelling.To investigate the general principles of the NATM,this study focused on tunnelling practises in the Bolu tunnel,and evaluated the conditions under which the NATM practises could be effective.The Bolu tunnel project was designed following the NATM principles.It is evident that practises adopted in this tunnel are important with respect to the NATM.In addition,it shows that the solutions to the problems encountered in this tunnel are consistent with the NATM principles.Finally,the study determines the ground types of the NATM principles and proposes associated updates.
文摘Based on the construction of high risk tunnels in Guiguang-Guangzhou high-speed railway, several new technologies were developed for high-risk tunnel con- struction. First, an integrated advanced geological predic- tion was developed for tunneling in karst area. Then, a new system of ventilation by involving the dedusting technol- ogy was proposed and used in the field, which received a good air quality. Finally, a method to minimize the dis- tance between the working face and the invert installation was proposed by optimizing the invert installation and adopting the micro bench method. Applying the method to the project obtained an excellent result. The achievement obtained for this study would be able to provide a valuable reference to similar projects in the future.
文摘Mass movements are very common problems in the eastern Black Sea region of Turkey due to its climate conditions, geological, and geomorphological characteristics. High slope angle, weathering, dense rainfalls, and anthropogenic impacts are generally reported as the most important triggering factors in the region. Following the portal slope excavations in the entrance section of Cankurtaran tunnel, located in the region, where the highly weathered andesitic tuff crops out, a circular toe failure occurred. The main target of the present study is to investigate the causes and occurrence mechanism of this failure and to determine the feasible remedial measures against it using finite element method(FEM) in four stages. These stages are slope stability analyses for pre-and postexcavation cases, and remediation design assessments for slope and tunnel. The results of the FEM-SSR analyses indicated that the insufficient initial support design and weathering of the andesitic tuffs are the main factors that caused the portal failure. After installing a rock retaining wall with jet grout columns and reinforced slope benching applications, the factor of safety increased from 0.83 to 2.80. In addition toslope stability evaluation, the Rock Mass Rating(RMR), Rock Mass Quality(Q) and New Austrian Tunneling Method(NATM) systems were also utilized as empirical methods to characterize the tunnel ground and to determine the tunnel support design. The performance of the suggested empirical support design, induced stress distributions and deformations were analyzed by means of numerical modelling. Finally, it was concluded that the recommended stabilization technique was essential for the dynamic long-term stability and prevents the effects of failure. Additionally, the FEM method gives useful and reasonably reliable results in evaluating the stability of cut slopes and tunnels excavated both in continuous and discontinuous rock masses.
基金support of China University of Geosciences (Wuhan)
文摘Estimation of tunnel diameter convergence is a very important issue for tunneling construction,especially when the new Austrian tunneling method（NATM） is adopted.For this purpose,a systematic convergence measurement is usually implemented to adjust the design during the whole construction,and consequently deadly hazards can be prevented.In this study,a new fuzzy model capable of predicting the diameter convergences of a high-speed railway tunnel was developed on the basis of adaptive neuro-fuzzy inference system（ANFIS） approach.The proposed model used more than 1 000 datasets collected from two different tunnels,i.e.Daguan tunnel No.2 and Yaojia tunnel No.1,which are part of a tunnel located in Hunan Province,China.Six Takagi-Sugeno fuzzy inference systems were constructed by using subtractive clustering method.The data obtained from Daguan tunnel No.2 were used for model training,while the data from Yaojia tunnel No.1 were employed to evaluate the performance of the model.The input parameters include surrounding rock masses（SRM） rating index,ground engineering conditions（GEC） rating index,tunnel overburden（H）,rock density（？）,distance between monitoring station and working face（D）,and elapsed time（T）.The model’s performance was assessed by the variance account for（VAF）,root mean square error（RMSE）,mean absolute percentage error（MAPE） as well as the coefficient of determination（R2） between measured and predicted data as recommended by many researchers.The results showed excellent prediction accuracy and it was suggested that the proposed model can be used to estimate the tunnel convergence and convergence velocity.
文摘The New Austrian Tunneling Method （NATM） has been widely used in the construction of mountain tun- nels, urban metro lines, underground storage tanks, underground power houses, mining roadways, and so on, The variation patterns of advance geological prediction data, stress-strain data of supporting struc- tures, and deformation data of the surrounding rock are vitally important in assessing the rationality and reliability of construction schemes, and provide essential information to ensure the safety and scheduling of tunnel construction, However, as the quantity of these data increases significantly, the uncertainty and discreteness of the mass data make it extremely difficult to produce a reasonable con- struction scheme; they also reduce the forecast accuracy of accidents and dangerous situations, creating huge challenges in tunnel construction safety, In order to solve this problem, a novel data service system is proposed that uses data-association technology and the NATM, with the support of a big data environ- ment, This system can integrate data resources from distributed monitoring sensors during the construc- tion process, and then identify associations and build relations among data resources under the same construction conditions, These data associations and relations are then stored in a data pool, With the development and supplementation of the data pool, similar relations can then he used under similar con- ditions, in order to provide data references for construction schematic designs and resource allocation, The proposed data service system also provides valuable guidance for the construction of similar projects.
文摘The Geheyan Power Station on the Qingjiang river has four inlet tunnels, on the right bank, with its excavation diameter of 11.3 m to 12.5 m, after lining diameter of 9.5 m, axis to axis spacing of 24 m. The thickness of the pillar between tunnels should usually be more than two times of tunnel diameter to ensure the stability of surrounding rock during excavation. In this paper, the excavation methods of tunnels with the pillar thickness as small as the tunnel diameter, such as smooth surface blasting, shotcrete support protection, are emphatically discussed.
